The Accordion Severity Grading System of Surgical Complications

Steven M. Strasberg, MD; David C. Linehan, MD; William G. Hawkins, MD


Annals of Surgery. 2009;250(2):177-186. 

In This Article

Abstract and Introduction


Background: A severity grading system is essential to reporting surgical complications. In 1992, we presented such a system (T92). Its use and that of systems derived from it have increased exponentially. Our purpose was to determine how well T92 and its modifications have functioned as a severity grading system and to develop an improved system for reporting complications.
Methods: 129 articles were studied in detail. Twenty variables were searched for in each article with particular emphasis on type of study, substitution of qualitative terms for grades, grade compression, and cut-points if grade compression was used. We also determined relative distribution of complications and manner of presentation of complications.
Results: T92 and derivative classifications have received wide use in surgical studies ranging from small studies with few complications to large studies of complex operations that describe many complications. There is a strong tendency to contract classifications and to substitute terms with self evident meaning for the numerical grades. Complications are presented in a large variety of tabular forms some of which are much easier to follow than others.
Conclusions: Current methods for reporting the severity of complications incompletely fulfill the needs of authors of surgical studies. A new system-the Accordion Severity Grading System-is presented. The Accordion system can be used more readily for small as well as large studies. It introduces standard definition of simple quantitative terms and presents a standard tabular reporting system. This system should bring the field closer to a common severity grading method for surgical complications.


Postoperative complications are important outcome measures in studies of surgical procedures. In addition to the type of complication the severity of the complication should be clearly and consistently reported. In 1992, we proposed a classification of negative outcomes of surgery and a severity grading system for complications.[1] It subdivided negative postoperative outcomes into complications, sequelae, and failures to cure, and then proceeded to define the term "complication" as it relates to surgical procedures.[1] To grade severity of complications it relied heavily on the type of intervention used to manage the complication, and whether there was permanent disability or death. These variables were selected as the indicators of severity of complications because of their lack of subjectivity and the fact that they were usually readily available to investigators-even in retrospective chart analyses. Four grades containing 5 levels of complications were described. This system has been used extensively in describing complications in surgical studies. For the purposes of this report, the classification system will be referred to as T92.[1]

In 2005, Dindo et al described a "modification" of T92.[2] This revision expanded the classification to 5 grades containing 7 levels of severity.[2] The amended classification added precision by requiring information regarding whether the intervention provoked by the complication involved a general anesthetic, whether ICU admission for organ failure was needed and if so complications were subdivided by the extent of organ failure present. The utility of the modified classifiction was tested by relating it to the extent of surgical procedure, length of hospital stay, and by providing sample cases for surgeons in 10 surgical centers to classify. This revised classification has also been used widely in surgical studies. A less extensive modification, made by Martin et al[3,4] is referred to as The Memorial Sloan Kettering (MSKCC) severity grading system; this modification is conceptually very similar to T92 but differs in details such as numbering. The 3 classifications are shown in Table 1 and Table 2 .

The purpose of the present study was to determine how well T92 and its modifications have actually functioned as a severity grading system for postoperative complications in surgical studies. All studies using T92 and its modifications as the basis for classifying postoperative complications were examined, searching for positive features and shortcomings in actual practice. On the basis of this analysis, we propose a modified severity grading system geared toward making the classification more useful in studies of different size and complexity. The modification presents a flexible classification system referred to as the "Accordion Classification." It adopts internally evident terminology and presents a standardized format for a complication reporting table, which is available on an open website.


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